1. Field of the Invention
The present invention relates to a specific gravity measuring device to be used for measurement of various substance including not only solid substance consisted of wide variety of solid materials including noble metal, alloy, synthetic resin, ceramics, rubber, fiber and so forth, but also powder state substances, granular state substances, liquid state substances.
2. Description of the Related Art
In general, in order to know specific gravity of solid state substance having unknown volume, the volume of the solid state substance is, at first, derived utilizing Archimedes principle. Namely, using a principle that buoyancy of substance in a fluid is equal to a weight of the fluid detruded by the solid state substance, a weight of the solid state substance in air and a weight in liquid are measured in the condition completely sinking in the liquid having known specific gravity (normally, water having specific gravity 1) to derive a volume of the solid state substance from the buoyancy (g) as difference of the weight in air and the weight in liquid, and a specific gravity (g/cm3) of the liquid. Then, the specific gravity of the objective solid state substance is derived as weight in air (g)/volume (cm3). When the liquid to be used is water, since the weight (g) thereof is equal to a value of the volume (cm3), the value of buoyancy (g) matches with the value of volume (cm3) of measuring object as is. Accordingly, specific gravity (g/cm3) of the measuring object can be expressed by the following equation.
Specific Gravity=Weight in Air/Buoyancy=Weight in Air/(Weight in Air)xe2x88x92(Weight in Water)
The conventional specific gravity measuring device includes a first container containing a liquid, a second container disposed in the first container in non-contact manner and permitting the liquid in the first container flowing in and out, an aerial mounting portion supported in the second container for measuring weight of the measuring object in air, and a weighting equipment receiving and supporting the second container to derive and display specific gravity from the weight when the measuring object as mounted on the aerial mounting portion and the weight when the measuring object is sunk within the second container. On the other hand, as the conventional specific gravity measuring device, it has been known a device including a main body of the weighting machine having a hook, and a lifting platform lifting a container filled with water up and down. At first, the measuring object is hanged by the hook to measure the weight in air, then the lifting platform is lifted up to completely sink the measuring object in water for measuring the weight in water for deriving the specific weight from both measured weight to display.
Furthermore, there is another specific gravity measuring device which has a construction to measure buoyancy instead of measuring the weight in water (liquid). Such device is constructed by placing the aerial mounting portion within the first container filled with the liquid and disposing the second container permitting liquid flowing in and out, within the first container in non-contact manner to measure the weight when the measuring object is mounted on the aerial mounting portion by receiving and supporting the weighting equipment the first container. With such device, after measuring the weight of the measuring object as mounted on the aerial mounting portion, the weight of the first container is measured in the condition where the measuring object is sunk in the water in the second container for deriving buoyancy to derive the specific gravity from the buoyancy and the weight in air.
Measurement of specific gravity is exclusively used as means for knowing purity of substance. In the recent years, associating with highly advancing of industrial technology, measurement of specific gravity is frequently used for quality assurance, analysis and so forth of substance, such as noble metal, alloy, synthetic resin, ceramics, rubber, fiber, solid state substance formed of composite material of these, and further even substance including powder state substance, granular state substance. However, since the measurement of specific gravity is means for basic test, inspection and measurement, it is an item to eliminate work load in viewpoint of production ability of the substance while it is important. All of the conventional specific gravity measuring device requires two stage measurement by measurement of weight of the measuring object in air and measurement of weight or buoyancy of measuring object in water (liquid) by sinking the measuring object in water (liquid) to require labor hour and substantial measuring period. Particularly, when measurement of specific gravity is performed for different measuring objects sequentially, the conventional devices are quite inefficient.
Accordingly, it is the first object of the present invention to provide a specific gravity measuring device which can certainly and instantly measure specific gravity of various solid state substances through one measurement operation quite simply.
A second object of the present invention is to provide a specific gravity measuring device which does not require measurement of weight of measuring object in air, can simultaneously measure a weight in liquid and a buoyancy by two measuring portion only by mounting the measuring object on a measuring object receptacle member in sinking condition within a liquid bath for deriving and displaying specific gravity from result of measurement so that specific gravities of various substances can be quite simply, instantly and certainly measured by one measuring operation, and can be particularly efficient when specific gravities of various measuring objects are measured sequentially.
Other objects and advantages will become clear from the following discussion in terms of the preferred embodiment.
In order to accomplish the above-mentioned and other objects, a specific gravity measuring device, according to the first aspect of the present invention, comprises:
a liquid bath filled with a liquid;
a first measuring portion receiving and supporting the liquid bath;
a measuring object receptacle member arranged in the liquid bath in a condition dipped in the liquid;
a second measuring portion supporting the measuring object receptacle member in non-contact condition relative to the liquid bath:
an arithmetic unit deriving a specific gravity value on the basis of measured values of the first and second measuring portions; and
a display unit for displaying the specific gravity value derived by the arithmetic unit;
the measuring object being mounted on the measuring object receptacle member sinking in the liquid within the liquid bath in a condition sinking in the liquid,
the first measuring portion measuring increase of weight associating with dipping of the measuring object in the liquid by the first measuring portion, as buoyancy;
the second measuring portion acting simultaneously with the first measuring portion and measuring a weight of the measuring object in the liquid by the second measuring portion;
the arithmetic unit deriving the specific gravity value from a measured value of the buoyancy and the weight in liquid for displaying on the display unit.
In the preferred construction, the arithmetic means is provided with arithmetic correction means. The measuring object receptacle member may be porous member, such as net form member.
Also, the first measuring portion, the second measuring portion, the arithmetic unit and the display unit may be integrally assembled in a main body of weighting equipment, and the measuring object receptacle member nay be hanged by hanging member vertically extending from the second measuring portion. The main body of the weighting equipment may be constructed with a first weighting equipment forming the first measuring portion and a second weighting equipment forming the second measuring portion, the first and second weighting equipments may be integrally connected by a connection frame with defining a gap portion there between. Also, the hanging member may be a wire member including a lower horizontal member fixed to a receptacle seat of the second measuring portion, a support member extending upwardly from the lower horizontal member and an upper horizontal member extending from upper end portions of the support member beyond an upper edge of the liquid bath and extending horizontally in opposition to an upper surface of the liquid bath. The measuring object receptacle member may be hanged by a cable connected to the upper horizontal member at the upper portion and depending into the liquid bath.
The specific gravity measuring device may further comprise a floating preventing member for holding a measuring object lighter than the liquid in the liquid bath on the measuring object receptacle member in sinking condition.
According to the second aspect of the present invention, a specific gravity measuring device comprises:
a liquid bath filled with a liquid having known specific gravity;
measuring object mounting means disposed within the liquid bath for mounting a measuring object in a condition sinking in the liquid;
first measuring means for directly receiving weight of the liquid bath and deriving a buoyancy indicative value representative of buoyancy of the measuring object on the basis of a weight increase when the measuring object is placed on the measuring object mounting means and known specific gravity of the liquid;
second measuring means for supporting the measuring object mounting means, directly receiving weight of the measuring object mounting means and the measuring object as placed on the former and deriving a weight in liquid indicative value representative of weight of the measuring object in water;
arithmetic means for receiving the buoyancy indicative value and the weight in liquid indicative value for deriving a specific gravity indicative value representative of specific gravity of the measuring object; and
display means for displaying the specific gravity indicative value.
In the preferred construction, the specific gravity measuring device may further comprises initial setting means for setting initial value of the buoyancy indicative value and the weight in liquid indicative value in a condition where the measuring object is not loaded on the measuring object mounting means.
The second measuring means may support the measuring object mounting means in floating condition relative to the liquid bath.
The specific gravity measuring device may further comprise retainer means for retaining the measuring object on the measuring object mounting means.